Effects of $Z_b$ states and bottom meson loops on ${\rm Y}(4S)\to {\rm Y}(1S,2S){\pi }^{+}{\pi }^{-}$ transitions

Abstract

We study the dipion transitions ${\rm Y}(4S)\to {\rm Y}(nS){\pi }^{+}{\pi }^{-}$ $(n=1,2)$. In particular, we consider the effects of the two intermediate bottomoniumlike exotic states $Z_b(10610)$ and $Z_b(10650)$ as well as bottom meson loops. The strong pion-pion final-state interactions, especially including channel coupling to $K\bar{K}$ in the $S$-wave, are taken into account model-independently by using dispersion theory. Based on a nonrelativistic effective field theory we find that the contribution from the bottom meson loops is comparable to those from the chiral contact terms and the $Z_b$-exchange terms. For the ${\rm Y}(4S)\to {\rm Y}(2S){\pi }^{+}{\pi }^{-}$ decay, the result shows that including the effects of the $Z_b$-exchange and the bottom meson loops can naturally reproduce the two-hump behavior of the $\pi \pi$ mass spectra. Future angular distribution data are decisive for the identification of different production mechanisms. For the ${\rm Y}(4S)\to {\rm Y}(1S){\pi }^{+}{\pi }^{-}$ decay, we show that there is a narrow dip around 1 GeV in the $\pi \pi$ invariant mass distribution, caused by the final-state interactions. The distribution is clearly different from that in similar transitions from lower ${\rm Y}$ states, and needs to be verified by future data with high statistics. Also we predict the decay width and the dikaon mass distribution of the ${\rm Y}(4S)\to {\rm Y}(1S)K^{+}{K}^{-}$ process.

25 pages, 8 figures, predictions of the decay width and the dikaon mass distribution of the ${\rm Y}(4S)\to {\rm Y}(1S)K^{+}{K}^{-}$ process added, more discussions added

References in corpus (11)

• The pion-pion scattering amplitude. IV: Improved analysis with once subtracted Roy-like equations up to 1100 MeV
• Quarkonia and their transitions
• Effect of charmed meson loops on charmonium transitions
• MO analysis of the high statistics Belle results on $\gamma \gamma \to {\pi }^{+}{\pi }^{-},{\pi }^0{\pi }^0$ with chiral constraints
• Hadronic Decays of the X(3872) to chi_{cJ} in Effective Field Theory
• Confirming the molecular nature of the $Z_b(10610)$ and the $Z_b(10650)$
• Anomalous decay and scattering processes of the eta meson
• Dispersive analysis of the scalar form factor of the nucleon
• Scalar Resonance Contributions to the Dipion Transition Rates of ${\rm Y}(4S,5S)$ in the re-scattering model
• Precision lattice QCD computation of the $B^{\ast }B\pi$ coupling
• Measurement of the branching fraction for the decay Upsilon(4S) -> Upsilon(1S)pi+pi-

Cited by in corpus (20)

• Pentaquark and Tetraquark states
• Exotic to standard bottomonium transitions
• Nature of the $Y(4260)$: A light-quark perspective
• Pole analysis on the doubly charmed meson in $D^0{D}^0{\pi }^{+}$ mass spectrum
• Information in AdS/QCD: mass spectroscopy of isovector mesons
• Insights into $Z_b(10610)$ and $Z_b(10650)$ from dipion transitions from ${\rm Y}(10860)$
• Study of $\eta$ and dipion transitions in ${\rm Y}(4S)$ decays to lower bottomonia
• Heavy meson thresholds in Born-Oppenheimer Effective field theory
• Weak Decays of Triply Heavy Tetraquarks $b\bar{c}b\bar{q}$
• The $Z_b$ structures in a constituent quark model coupled-channels calculation
• Hidden-bottom hadronic transitions of ${\rm Y}(10753)$
• Isospin-conserving hadronic decay of the $D_{s1}(2460)$ into $D_s{\pi }^{+}{\pi }^{-}$
• Simultaneous description of the $e^{+}{e}^{-}\to J/\psi \pi \pi (K\bar{K})$ processes
• Hunting for $X_b$ via hidden bottomonium decays $X_b\to \pi \pi {\chi }_{bJ}$
• On the emergence of heavy quark spin symmetry breaking in heavy quarkonium decays
• $D$ wave bottomonia production from $Z_b^{(\prime )}$ decay
• Study of the $Y(4660)$ from a light-quark perspective
• $\varphi (2170)$ decaying to $\varphi \pi \pi$ and $\varphi K\bar{K}$
• Chromopolarizability of charm-beauty quarkonium from $B_c(2S)\to B_c\pi \pi$ transition
• Exotic hadrons associated with $b$-quark